Abstract: Vibration measurements of four actual rigs under jack-up condition have been carried out, with their natural frequency and damping ratio obtained. When analysed with SAP5 Program, the rig is taken as a space frame structure, the chords of the legs as beam elements, all the internal bars as truss elements and the platform itself as a rigid body. A good agreement is found between the measured freguencies and the calculated values. The dynamic response of rigs to wave load is studied, which shows that the dynamic effect should be considered in the fatigue analysis of rigs.

摘要： 自升式钻井平台在钻井作业时与固定平台相似。对四条具有三角形桁架桩腿的平台进行了振动测量,得出了自振特性(频率,振型,阻尼);用SAP5程序分析这些平台时,将平台视作空间框架结构,而桩腿的弦枰视为梁元,腹杆视为桁条元,平台本身视为无限刚,计算了90米和16米水深的情况,计算结果和实测结果相符。用设计波法及波谱法,计算了在91.5米水深,两种波高(15.3米和3米)情况下的波浪力及其在平台上的反应。文中讨论了平台在浅水区域钻井时悬臂桩腿的风激振动,在90米水深时的平台振动。